Modern rear house extension with glass doors in London by Forge Build
EXTENSIONS

House Extensions

Rear, side-return and wrap-around extensions delivering more space, more light and more value — planned and built end-to-end.

4.9/5
Average Rating
10-Year
Workmanship Warranty
Fixed
Price Contracts
95%
On-Time Delivery

Space That Feels Built-In

We manage survey, design, planning or lawful development checks, structural calculations, shell build and interiors. Expect a seamless transition between old and new with daylight, ventilation and flow designed in.

  • Rear, side-return & wrap-around extensions
  • Planning/PD advice & structural design included
  • High-performance glazing & rooflights for daylight
  • Fixed price, clear programme, weekly updates

Typical Timelines

Rear Extension
8–12 weeks

Shell, rooflight(s), glazing & interior fit-out.

Side-Return
10–14 weeks

Steelwork, infill roof & kitchen re-plan.

Wrap-Around
12–18 weeks

Complex structure & services re-routes.

Add-ons (Kitchen/Joinery)
+2–6 weeks

Lead times & custom specifications apply.

Indicative only — confirmed after survey & design pack.

How We Deliver

1

Survey & Feasibility

Measured survey, layout options, daylight & flow.

2

Design & Approvals

Drawings, structural calcs & PD/planning as needed.

3

Build & Fit-Out

Steelwork, shell, roofing, glazing & interiors.

4

Sign-Off & Aftercare

Certification, warranties & aftercare.

Case Study: Ealing Rear Extension

A full-width single-storey rear extension transformed this 1930s terraced property in Ealing into a bright, open-plan kitchen and dining space. We focused on structure, natural light and energy efficiency, achieving a seamless connection between home and garden.

  • Budget: £98k
  • Duration: 10 weeks
  • Outcome: +22m² living space; EPC improved D→C
After extension — open-plan rear extension with glazing
Before extension — original rear elevation

Drag the circle to compare before/after.

Featured Projects

Recent extensions and major refurbishments delivered across London.

Hackney whole-home renovation with rear extension
HACKNEY

Whole-Home Renovation

Services upgrade, new layout, energy efficiency improvements.

View details
Islington loft conversion master suite
ISLINGTON

Loft Conversion

Mansard roof with ensuite; maximised daylight and smart storage.

View details
Hampstead full house refurbishment with premium finishes
HAMPSTEAD GARDEN SUBURBS

Full Refurbishment

Victorian terrace re-plan with new services, bespoke joinery and premium finishes.

View details

Client Reviews

“The new kitchen-diner is stunning and the build was smooth.”

Sara — Fulham

“Fixed price and weekly updates made it stress-free.”

Josh — Islington

“Quality finish, great communication. Highly recommend.”

Priya — Ealing

Accreditations & Partners

CHAS Accredited CHAS Accredited
FMB Member FMB Member
SafeContractor SafeContractor
TrustMark TrustMark

Areas We Cover

Forge Build proudly serves homeowners and developers across London and the South East, delivering extensions, conversions, and full refurbishments to the highest standards.

Don't see your area listed? We may still be able to help!

Call us to check: 020 3355 6146

FAQs

Do I need planning permission for an extension?

Many single-storey rear extensions fall under permitted development. We’ll advise and handle PD/planning as required.

Will you handle structural design and Building Control?

Yes, structural calcs, inspections and sign-off are included in our end-to-end delivery.

Can we live at home during the build?

Often yes. We’ll phase the works and aim to keep essential services running where feasible.

Ready to Extend Your Home?

Book a free site visit — get expert advice, a clear programme and a fixed-price quote.